Vapor fuel injector flameholder



April 6, 1965 w. c. COLLEY, JR

VAPOR FUEL INJECTOR FLAMEHOLDER Filed Aug. 27, 1962 fwiuaz IN V EN TOR. Max/4M 0.445;: ./e

ilymwww 3,176,465 Patented Apr. 6, 1965 United States Patent Ofi ice VAPGR FUEL INJECTOR FLAMEHOLDER William C. Culley, Jr., West Chester, Ohio, assignor to ,General Electric Company, a corporation of New York Filed Aug. 27, 1962, Ser. No. 219,695 8 Claims. (Cl. 6039.72)

. such engines are required to operate over a wide range of flight speeds, it is necessary to mount flameholders within the burner as is done in present day engines. A

' convenient and well-known method of cooling these fiameholders is to pass through them the fuel ultimately consumed in the burner.

It is anticipated that the fuel to be used in these high speed engines will be in a gaseous state at the time of use. It may be a fuel which is a gas at normal temperatures, such as hydrogen or methane, and which is stored aboard the aircraft as an extremely cold liquid in insulated tanks, or it may be a fuel which is normally a liquid, such as highly refined kerosene or a pure liquid hydrocarbon compound. In either case, the fuel will be employed to cool many parts of the engine and airframe, and in so doing will be heated to the extent that it will be in gaseous form when delivered to the burner. Thus, the

fuel will be burned as a vapor.

It is further desired to burn as close to stoichiometric as possible. This, as is well known, is the chemically correct mixture of fuel and air which provides just enough fuel to theoretically consume all the oxygen in the air and no more. The stoichiometric mixture varies for different fuels and this mixture approximately corresponds to the highest temperature mixture obtainable or, in other words, the hottest flame obtainable which therefore provides the most energy release. Such a desired mixture encounters the standard problem, whether in aircraft or other internal combustion engines, of uniform fuel distribution. In a reaction engine, this requires a most uniformly distributed fuel across the entire area of the burner. This provides the highest efliciency obtainable and a close approach to the stoichiometric mixture. In addition, this must be done in an extremely fast moving fluid stream.

It is known to use V-gutters and inject fuel in various ways in the vicinity of the V-gutter. The V-gutter provides a stagnant or dwell region for burning to initiate and/or occur. It is further known to use fuel injection tubes which contain orifices injecting the fuel at right angles to the air stream and various types of these injectors have been successfully built. One of the problems A encountered is that the fuel jets at very high fuel flows penetrate so completely into the air stream that they leave the region next to the V-gutter with very little fuel. Since the V-gutters purpose is flameholding, obviously it is necessary to have fuel in the vicinity of the V-gutter if it is to function. It is common to put additional orifices in the I tubes to inject fuel in the direction of the air flow. It has 7 down the side of the V-gutter plates so that it will stay in the immediate vicinity. By itself, this does not give uniform distribution since there is no penetration of the fuel into the main flow of the air stream.

The main object of the present invention is to provide a fuel cooled vapor fuel injector flameholder that is operable over a wide range of fuel air ratios and the optimum fuel distribution is automatically attained at all fuel flows.

A further object is to provide such an injector flameholder which combines both normal or transverse injection and upstream injection in such a Way as to provide uniform fuel distribution.

A further object is to provide deflectors in conjunction with the upstream injection to cooperate with the transverse injection and provide the uniform fuel distribution.

Briefly stated, the invention provides a vapor fuel injector flameholder for a combustion chamber which uses a hollow tube closed upon itself and conducting vapor fuel. The tube is disposed across the combustion chamber and has a pair of plates secured to it and extending downstream to form a V-gutter fiameholder. A series of diametrically opposed spaced apertures in the tube direct fuel transversely of the combustion chamber and a second series of spaced apertures in the tube direct fuel upstream and substantially at right angles to the first series. A deflector is placed over each of the second series of apertures and the deflector is spaced from the tube to intercept the emerging fuel flow and direct the flow as a film along the V-gutter plates.

While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention, it is believed the invention will be better understood from the following description taken in connection with the accompanying drawing in which: I

FIGURE 1 is a partial cross-sectional view of a typical spaced ring fuel injector as used in an afterburner,

FIGURE 2 is an end view of FIGURE 1,

FIGURE 3 is a partial cross-sectional view of the invented injector flameholder, and

FIGURE 4 is a partial side view of the flameholder showing the spaced deflectors.

Referring first to FIGURE 1, there is shown a partial cross-section of a reaction engine having a casing 10 forming a combustion chamber which, as shown, may be an afterburner or augmentor section 11 and an inner cone I2 guiding the motive fluid or exhaust gases downstream from a turbine not shown. Further combustion may take place in section 11 and to this end there is provided a fuel injector flameholder arrangement generally indicated at 13 which is disposed transversely across the combustion section 11. The injector flameholder 13 may comprise a series of concentric tubes 14 that are supported by hollow struts which struts and tubes may convey fuel for injection into section 11. Tubes 14 may be arrangements other than concentric tubes but this arrangement is preferable. The fuel normally will be vaporized, having been used elsewhere as a cooling medium and having been vaporized in the process.

The individual vapor injector flarneholder is shown in detail in FIGURE 3. In order to provide a stagnant region and fiameholding capability, tube 14 has a pair of flat spaced plates 15 extending downstream from the tube to form a V-gutter flameholder. The plates normally diverge as shown an amount dependent on the particular environment in which they are to be used. As is well known, a recirculation zone 16 is formed at the downstream end of the plates at which a pilot flame may dwell due to the stagnant condition in the recirculation zone. It is desired to obtain uniform fuel injection across section II and to this end tube 14 is provided with a first series of diametrically opposed apertures 17 which are axially spaced along the tube as shown in FIGURE 4. These apertures are used. to injectthe fuel transversely to the combustion chamber as shown by the arrow in FIGURE 3 and this form of injection is known. At high fuel presaway from aperture for adequate defiecting,cooling, and 'distributing'of the fuel; The spaced deflectors are preferred over a continuous deflector for the same sures the penetration of the transverse streams from aper- 7 tures 17 leave the area adjacent theflaineholder starved of fuel. A plurality of the concentric tubes 14, arranged as shown in'FIGURESl and 2, provide a transverse blanket of fuel across section 11, but, in the immediate vicinityof the flameholder, without more, the fuel supply is'in-i adequate and the fiameholder does not function. To onto this, a second. series of spacedapertures 13 isprovided in the tube; and directed upstream of the tubeasshown in; FIGURE 3, It is to be notedithat this aperture .18 alone, injecting fuel" upstream, would penetrate some distance upstream and then mix .Withthe approaching air and,

being slightlydiluted by that air, it would be carried back on the flameholder and would not be as eifective as if it place. In otherwords; the fuel-air ratio wo'uldtend to decrease. providing an insufiicient burning mixture adjacent the flameholder.

The present invention includesa means for holding the fuel in the vicinity of the injector'andthis is done by prof viding a spaced deflector member 19 which maybe sew cured-bystrap '20to the tube as shown in FIGURE 4.-

The purpose of the' detlec't'or is to holdithe' vapor fuel exiting from aperture 18" in the immediate vicinity of the injector and thus allow it to how down ithe'side of the flameholder' plates as a sheet or film as shown by. the

arrows in FIGURE 3. Preferably, a single aperture 18 is shown centrally disposed so thatthe fuel 'will split upon 1 hitting the top and flow down both sides; and thus lose, most of thefinjection energy in the process. Thisis de-- reason in that portions of'the continuous deflector would be too far from; the high velocity jet from aperture 18 resulting in poor distribution and inadequate cooling. Consequentlyp the spaced deflector arrangement is albe tter combustion arrangement formore efiicient burning} Preferably, to avoid spillage of fuel from aperture 18 into the side region between deflectors and consequent 're- Eduction of the film of pilot fuel downplates 15,'each de :fiector is provided with endplates 22 (which may be a .to the underside of the deflectors.

continuation of, or part of, straps confining the fuel With ;the arrangement just described, it will be apparv ent that at low fuel flows the penetration of fuel from apertures 17 is slightand the-two fuel streams, from-aperhad been held in the vicinity of the'injector inthe first 'tures 17'and the film fromapertures 18, merge to concentrate the fuel inthe vicinity of the fia'meholder; *Athigh fuel flows, thejetsof fuelfr-om tapertures'l'i'. penetrate transversely well into the air stream'to' create'a nearly uniform fuel distribution while the fuel fromapertures 7 13 flows directly into the wake of the fiameholder thus insuring the maintenance of a combustible mixture in this region at all times. Thematic of the amount of fuel injected through apertureslito that through apertures 18 is 'regulatedby the number and size of the respective apertures." This ratio willnormaliy ,vary with the fuel em- 'ployed,- the operating conditions being encountered, and

'the physical arrangement of the fiameholders within a particular burner.

Cooling is provided by passing the fuel-directly. through the flameholder before burning a'n'djthus lighter construcsired since it is necessary to let the fuel'fiow za's a film along the plates. Furthermore, the use of thefuel, strika p V V p 7 at all burner fuelair rauosyet-flame-out due to overpeneing the inner surface ofldeflector, 19 serves at thesame timeto cool'it so that it does not burnawayr For best f I results, it has been found that the spacing of the deflector".

from the tube or the radial distancefil should be a maximum of one-fourth the diameter ofthetubeif a cylindri- 40" cal tube is used or substantially one-fourth the width of- I the'tube ifother than a cylindrical tube is used; Larger],

spacing results in insuflicient cooling o'f'the deflector by the fuel. Additionally, with a larger space, air circulates back under the deflector, permitting unwanted combustion between the deflector and tube. Furthermore, the deflec-- tor 19 preferably extends around the'tube approximately 1 1 the width of the tube as shown in FIGURE 3, In the preh 'ferredconcentric arrangement shown. this width .or .pro-

jected area is substantially the, diameter of the tube. I

Wider than, that 01" overhanging would tendto expose 7 more of the deflector to thehot gases in section ll andplace part of the deflector farther away from therelatively j cool jet of fuel through aperture '18 'to lowerthe cooling effectiveness of the fuel in theqverhangingportion.of thew: deflector; Additionally,;it is unneeded hardware adding additional structure and weight.

' Referring next to FIGURE "4,

it has been found thatlthis spacing betweentadjacent de flectors should not exceed the' tube 14' diameter;-,The I spacing between deflectors is required since the fuel from apertures 17 has a tendency to pickup the low' velocity' it can be seenthatthe 7 deflectorv 19 is spaced from an, adjacent similar deflector; there being a plurality of'deflectors around the tube 14. f

fiow from apertures 18 and to'carry both fuels out into the main stream. This tendency isavoided by providing; gaps between cleflectorsto remove the aperture 17 fuel from V the lowvelocity fuel dribblin'ges'a film down the plates 2 v 15. The maximum spacing isdesired as a limit in order to avoid getting too far frorn the transverse fuelapertures; 17 and thus moving theflameholdingE-portion ofjplate 15 too far-away from the fuelissuirig from apertures'l'l;

' Additionally,deflectors,191have'anaxial length'with'a maximum equal tojthe tube diameterg This is the axial len'gth alongthe" deflector. as shown in FIGURE" Greater than the maximum, partsaof the defiector get too,

7 in the light .of the above teachings.

I flectors are spaced from said tube a fourth the'widthof saidtube. V y

3'. Apparatus as described. in claiml wherein said de-' fiectors extend over." said second series .of apertures the said tube diameter:

' tion may be used. Fuel is injected in such a mannerjthat the optimum fue'l' distribution isautomatically obtained tration of the fuel .jets is avoided. Further, the flame holder contains its own fuelmanifold thus simplifying the ILA vapor fuel-injector-flameholder for a reaction en- "gine combustion chamber comprising,

a hollow tube for conducting vapor fuel and disposed across the combustion chamber,

apair" of plates securedto and extending downstream V j from thetube to 'for'ma V-gutter flameholder,

said tube having a first series of, diametrically opposed spaced apertures for directing fueltransversely of the fcombustion chamber,

a sec'on'd series er spaced 7 upstreamthereof,

and a deflector over tures,'-":"1...; 7 said deflector being spaced from said tube and conform apertures said tube directed ing in curvature .therewithtoldirect fuel "from said 7 secondaperturesfas a film along'said plates. 7 2;. Apparatus as describedin claim l wherein said demaximum of one projected width of said tubes;

4, Apparatus as described in 61p lwhereins'aid hollow tube is cylindrical and said deflectors are spaced from said tube a maximum 0f one fourth saidlube-diameter.

' Y :5 Apparatus as described "in .c'la-iin 4'wherein said' detlectorshave a maximumlehgth a longtsaidgtube equal to.

each of said 'Seconidseries of aper- 6. A vapor fuel injector-fiameholder for a reaction engine combustion chamber comprising,

a hollow vapor fuel conducting cylindrical tube closed in a circle upon itself and disposed transversely across the combustion chamber,

a pair of flat spaced diverging plates secured to said tube to form therewith a V-gutter flameholder with rounded upstream apex,

said tube having a series of diametrically opposed spaced apertures for directing fuel transversely of the combustion chamber,

a second series of spaced apertures in said tube directed upstream thereof,

a deflector over each of said second series of apertures spaced from said tube and concentric therewith,

said deflector covering the width of said tube to intercept fuel flow from said apertures and direct it as a film along said plates.

7. Apparatus as described in claim 6 wherein each of said deflectors has an end plate to prevent spillage over the end of the deflectors.

8. Apparatus as described in claim 6 wherein each of said deflectors is spaced from said tube a maximum of one fourth the diameter of said tube and is provided with an end plate to prevent fuel spillage over the end of the deflectors.

References Cited by the Examiner UNITED STATES PATENTS 2,949,012 8/60 Ferric et al. Gil-39.74

FOREIGN PATENTS 1,245,920 10/60 France. 1,133,185 7/62 Germany.

CARLTON R. CROYLE, Primary Examiner.

ABRAM BLUM, Examiner. 

1. A VAPOR FUEL INJECTOR-FLAMEHOLDER FOR A REACTION ENGINE COMBUSTION CHAMBER COMPRISING, A HOLLOW TUBE FOR CONDUCTING VAPOR FUEL AND DISPOSED ACROSS THE COMBUSTION CHAMBER, A PAIR OF PLATES SECURED TO AND EXTENDING DOWNSTREAM FROM THE TUBE TO FORM A V-GUTTER FLAMEHOLDER, SAID TUBE HAVING A FIRST SERIES OF DIAMETRICALLY OPPOSED SPACED APERTURES FOR DIRECTING FUEL TRANSVERSELY OF THE COMBUSTION CHAMBER, A SECOND SERIES OF SPACED APERTURES IN SAID TUBE DIRECTED UPSTREAM THEREOF, AND A DEFLECTOR OVER EACH OF SAID SECOND SERIES OF APERTURES, SAID DEFLECTOR BEING SPACED FROM SAID TUBE AND CONFORMIN CURVATURE THEREWITH TO DIRECT FUEL FROM SAID SECOND APERTURES AS A FILM ALONG SAID PLATES. 